Printing telegraph apparatus



July 15, 1941- L. M. Po-rTs 2,249,040

PRINTING TELEGRAPH APPARATUS Filed June :23,` 19:58

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.ch $4 w '5 l. IBDFHJ-LNPRTVXZ246B8|BDF AICIEIGI MOQSUWYISSTS ACE INVENTOR. Loups M. PoTTs A ORNEY.

Patented July 15, 1941 UNirso PRYTENG TELEGRAPH APPARATUS Louis M. Potts, Evanston, Ill., assignor to Teletype Corporation, Chicago, Ill., a corporation of Delaware Application June 23, 1938, Serial No. 215,343

33 Claims.

This invention relates to printing telegraph systems and apparatus and more particularly to synchronous printers with continuously rotating type wheels.

The primary object of the invention is to provide a remotely controlled printing telegraph machine of simple and compact construction which may be employed economically with standard communication circuits.

Another object is to provide a printer with a tape spacing mechanism requiring a small amount of power by providing an efficient connection to the power source to advance the tape during the entire printing cycle corresponding t a character.

An important object of the invention is to provide a synchronous recorder responsive to a single signal impulse for each character having means effective within certain limits in the variation in the timing of the arrival of the signal corresponding to the same characters to insure uniform timing of the printing operation.

A further object is to .provide a type wheel phasing mechanism such that the type wheel may be uncoupled from a constantly rotating shaft by a special signal and recoupled in the correct phase position by a recording signal assigned to that function, which 'signal corresponds to a character position.

Another object is to provide a printer in which small signaling current are required by operating the signal magnet armature by power independent of the signals.

Specically, the printer according to the present invention comprises a type wheel continuously rotated by a synchronous. motor. A similar synchronous motor operates a transmitting device continuously rotating at the same speed as the type wheel. The transmitting device transmits short impulses at timed intervals corresponding to the characters to be recorded. The print hammer is operated at the proper time to record the selected characters which are impressed while the type wheel rotates, commonly called ily printing. The print hammer is operated by'a difierential gear comprising one element which constantly rotates with the type wheel and a second element normally at rest which carries the print hammer operating cam and tape spacing drum. The third or intermediate member is normally rotating. A signal controlled escapernent is provided which arrests the third member and permits the second member carrying the operating elements to rotate, to operate the print hammer, record the proper character, space the tape and permit the normal condition to return upon the completion of the recording cycle.

The transmitter, in addition to transmitting theV short recording impulses, may also transmit,

Awhen required, a special signal of a different Y to the arrested position of the type wheel, and

responsive to this signal the recording mechanism recouples the type wheel in the proper position and thus synchronizes and phases the type wheel with the transmitter. The short phasing impulse preferably corresponds to a blank position on the type wheel so that no record is made on the tape when the phasing impulse is received. There must be an interval equal to slightly more than the time of one revolution of the type wheel allowed between the special signal and the following short signal. Since the type wheel may require nearly a full revolution after the arresting impulse is received before the type wheel is arrested, the recording signal for phasing is so spaced with respect to the special signal, that the transmitter moves a corresponding angular amount between the strong arresting impulse and the recoupling impulse.

A better understanding oi the invention may be had from the following description, taken in conjunction with the accompanying drawing wherein like reference characters designate similar parts throughout the several views, and in which Fig. 1 is a graphical representation of the type.

of character selecting signal employed in operating the structural embodiment of the present invention, and illustrates the coincidence of the wave cycles of the alternating current with the character intervals;

Fig. 2 is an exploded lperspective view of one embodiment of the present invention;

Fig. 3 is a side elevational view of the printerY resents, for example, the letter K. A cycle of rotation of the type wheel shaft may be interpreted as the linear distance I8 between any one of the alphabetical or numerical characters illustrated in Fig. l, and the point thereafter at which that character first recurs. When no signals are transmitted, a continuous current condition prevails which is symbolized by the. shaded section II occurring above the median line I2. On the other hand, during a signal interval, the current condition I I is interrupted and is indicated in Fig. l by the interval I3. The frequency of the alternating current supplied to the synchronous motors of the transmitters and receivers is preferably such that one-half cycle corresponds to the time it takes the type wheel to rotate the distance between two consecutive characters. cated by the wave diagram indicated at 44 in Fig. l.

With the type of printer herein disclosed, a plurality of characters may be printed in a, single rotation of the type wheel. In other words, the closest characters which may be printed must be separated by a number of characters corresponding to a time interval slightly greater than the time required to record one character, or the printing time 38, which is indicated in Fig. 1 as being coextensive with five characters. If, then, there are forty characters on the type wheel, it would be possible to print eight characters in one revolution for the most favorable sequence of characters. Whereconsecutive characters more closely situated upon the type wheel periphery are attempted to be printed, it will require an additional rotation of the type wheel.

To the reduced end of shaft I 4 of a motor I5 is fixed a pinion gear I G (Figs. 2 and 4). The frame of the printer comprises a base plate I'I and vertical front and-back plates I8 and I9.

Pinion It meshes with a spur gear ZI which is integral with a sleeve 22 loosely carried on a shaft 23 journaled in front `and back plates IB and I8. Also integral with sleeve 22 are gears 24 and 25.

Having reference to Figs. 2 and 3, gear 25 is meshed with a pair of diametrically arranged planetary gears 45 and 4.5. Gear 45 is fixed to a short shaft journaled in a toothed disc 4l which in turn is loosely carried on shaft 23. Fixed to said Vshort shaft and on the opposite side of disc 41 is a companion `planetary gear `48. Likewise, gear 48 is fixed yto a short shaft also journaled in disc 4T, and to the opposite end of said short shaft is secured a planetary gear 49. Planetary gears 43 and 49 mesh with a. pinion gear I fixed to the shaft 23.

There is also fixed to shaft 23 and `adjacent to gear 5I a multitoothed cam disc 52. provided integrally on its face, confronting the gear 5I, with an annular ridge 44v having spaced square projections 53 (Figs. 3 'and 4) Cooperating with projections 53 is an acute angled bell crank lever 54, arm 55.01 which terminates in a laterally disposed tooth 38 which is adapted to cooperate with the oncoming projections 53y in a blocking manner. Lever 54 is also provided with an arm 56 which terminates in a curved cam follower portion to cooperate with the projections 53 for the purpose presently set forth. The arms 5.5 and 55 of lever 54 are in the same plane so that they are both in the path of rotation of projections 53, the arm 55 acting to block the projections 53, and said projections acting in their counterclockwise movement tov strike This relation is indi-l Disc 52 is cured to an adjusting screw against the cam shaped extremity of arm 56 -to rotate lever 54 clockwise. Arm 58 of lever 54 is also provided with a projection 5'! which acts, under certain conditions hereinafter described, to block the radial projections or teeth 58 on thev periphery of disc 42'. Lever 54 is fixed to a shaft 59 journaled in the plates I6 and IS. Also xed to shaft 53 to ythe rear of plate it* is an armature member EI. Armature member 6I carries a pole piece 62 which cooperates with the pole 53 of an electromagnet 54 (Fig. 4).

Loosely pivoted on shaft 59 is an acute angled bell crank holding lever 55, arm @E of 'which engages the multitoothed cam disc 52. Lever 65 is also provided with an arm Sl' which terminates in a laterally disposed projection 68 which, under certain conditions hereinafter described, is interposed between the teeth 53 on disc Lever arm Si has also integral therewith a cam follower portion 69 which cooperates with the cam teeth on the multitoothed cam disc 52. It is thus apparent' that arms G6 and 5i of lever (S5 are in the saine plane, since the extremity of arm 66 and the projection 69 of arm both cooperate with the periphery of the multitoothed cam 52.

Cam disc 52 controls the printing operation and hence actuates a cam follower arm ll secured pivotally to a shaft journaled in plates I8 and I9. Also xed to shaft l2 in front of plate IS, as viewed in Fig. 5, is a printing arm i3, which terminates in a hammer portion 74. Adjacent to portion i4 is fastened one end of the printing spring 15, the other end of which is se- 'Ii carried in a bracket ll integral with plate i8. In this manner the printing spring 'I5 may have its tension adjusted to produce the desired printing blow. Thus, when cam disc 52 rotates in response to the signal impulse, the arm I drops off the cam tooth or projection under power imparted thereto by spring 75, thereby actuating hammer portion 74 to effect printing of the selected character by forcing the tape 9| against an inked type wheel 34 carried on a shaft 2 journaled in front and rear plates I8 and I9.

Y In order to insure a sharp printing blow, a shock absorbing arrangement has been provided, Fig. 5, which comprises a bell crank lever I8 pivoted at 'I9 to plate I8. Lever 18 is provided with a horizontal arm which terminates in a laterally disposed portion 8i which overlies the end of printing arm 'I3 adjacent the portion l. Lever 'I8 is also provided with a vertical arm which carries at its upper extremity an adjusting screw 82which cooperates with a fixed stop 83. Lever 'I8 is normally urged in a counterclockwise direction against stop 83 byra spring S4. With this construction the effect of the bell crank lever 'I8 upon the printing arm 'I3 is controlled by the adjusting screw 82 which serves to regulate the rebound of the print hammer' and provides a useful means of obtaining clear impressions. Thus, just before the paper tape 9| touches the type wheel 34, the end of lever arm 'I3 engages end 8| of Vlever 18, rotates lever "I8 clockwise, and tensions spring 84. Spring 84 is stronger than spring l5, but the momentum attained by lever 73 is sufficient to overcome spring 84 and permit printing, but immediately thereafter spring 84 moves the hammer 'i4 away from the type wheel. A rapid printing action is desirable in all kinds of recorders but is especially desirable and Very necessary with fly printing.

Movement is imparted to tape SI by a knurledstrikes the projection 51 to hold disc 41 against rotation, planetary gears 45, 46, 48 and 49 will also be prevented from revolving around the pinions 25 and 5|. Under these conditions, rotation will be imparted to pinion 5I, and hence .shaft 23, to rotate the cam. disc 52 in a counterclockwise direction. The ratio between gears 24, 25, 26, 45, 45., 48, 49, and 5| is so chosen as to cause disc 41 to rotate through the angular distance 20 (Fig. 2) .between two adjacent teeth 58 on disc 41, while the type wheel 34 rotates through the anguiar distance of one character space. Observing that when a no-current impulse (signal impulse) is received, and the cam disc 52 is initiated into rotation, the cam lobe on the periphery thereof which has been cooperating with cam follower 69 of lever 65, moves away from the follower, and a diametrically disposed cam lobe on disc 52 acts upon arm 66 to rotate lever 65 counterclockwise. Thus, the lever 55 is rocked counterclockwise to bring projection 68 into the path ofteeth 58, and it is apparent that absolute coincidence between signal reception and the interception of a tooth 58 by projection 68 is not necessary. With the arrangement according to the present invention, certain limits of variation in the timing of signals is permitted so that, despite this fact, the timing of the operation of the print hammer is uniform, and consequently accurate recording of the selected character is nevertheless insured.

Immediately after the initiation of rotation of cam disc 52, arm 1l will become disengaged from the cam tooth or lobe thereon with which it has been engaged, to permit the performance of the printing operation. Printing arm 13 will thereupon respond to the action of printing spring 15, and print hammer 14 will be thrown against the periphery of the type wheel to effectV printing of the selected character. After the printing operation has been performed, cam disc 52 will, through arm 1l, return the print hammer 14 to its clockwise or lower position, thus tensioning spring 15, thereby storing energy therein to effect the succeeding operation.

As .previously described, immediately upon rotation cf cam 'disc 52, cam follower 59 rides off of the cam tooth with which it has been engaged, and lever arm 56 is operated by the oncoming cam tooth.v As cam follower 63 rides off of said cam tooth, projection 58 on arm 51 of the lever 55 is brought into the path of the oncoming radial tooth on disc 41, thus providing a secondary stop for disc 41. As disc 52 continues to rotate, the projections 53 thereon act on arm 56 of-bell crank 54 to rock lever 54 in a clockwise direction, thus acting to assist armature 6l into contact with the pole B3 of the selector magnet 34 where it is held by the current which has been re-established before the tip of lever 55 disengages the projection 53. It is recalled that the duration or interval of the signal impulse (no-current) is very short (Fig. l), therefore, themagnet 64 is energized again before the armature Gl is returned to its attracted or seized position.

When shaft 59 is returned as described, Aprojection 51 is disengaged from one of the teeth on disc 41, but just prior to this, projection 68 hadbeen moved into the path of another similar projection and is held there until the end of the cycle, thus assuring the completion of rotation of the cam disc 52. But, when projection 51 is disengaged, disc 41 moves a very short distance and engages projection 68 so that shaft 23 continues its rotation. After printing has been effected,- one of the projections 53 on the disc 52 also operates on arm 56 to restore lever 65 to its clockwise position, whereby at the end o f the cycle, projection 58 is disengaged from tooth.

58, and shaft 23 is again arrested by a projection 53 engaging the tip 39 of lever arm 55 which has been previously returned, and disc 41 resumes its rotation in step with the type wheel. At the end of the cycle, bell crank 55 is returned to its clockwise position, as viewed in Fig. 4, and is maintained there due to the fact that cam follower 69 rests again on one of the cam teeth or lobes on cam disc 52.

In the foregoing description of operation, it has been assumed that the operating shafts are rotating in synchronism and in phase. Moreover, the printing operation has been described rst since the phasing operation involves a printing cycle. Whenit is necessary to phase the apparatus, animpulse of strong current is transmitted to the receiver, and upon receipt thereof magnet 43 becomes energized. Having reference to Fig. 6, which `is a graphical representation of the current condition of the line during the phasing period, the shaded portion 96 represents the normal current condition of the line. rIhe phasing-initiating impulse is indicated by the higher shaded portion 91, and the stronger current comprising this impulse persists for the same length of time as a printing impulse period; namely, about two character spaces. It is recognized, of course, that when the magnet 43 has become energized by the impulse 91 of strong current, and the armature 3S has been attracted, the armature 39 will remain seized even after the stronger current Vhasbeen diminished in strength to the normal line current 96. For a reason which will presently appear, the armature 39 is permitted to remain seized for a .predetermined period, indicated as 98 `in Fig. 6, which is equivalent at least to one complete rotation of the type wheel 34. In this connection, the mechanism for transmitting the signals for performing the phasing operation is disclosed in copending application Serial No. 182,4221'ed December 30, 1937 by L. M. Potts. Thearrangement specifically shown in Fig. l0 of said application is particularly adaptable to the present apparatus.

Upon receipt of the phasing-initiating signal 91, magnet 43 will be energized and armature 39 will be attracted, thus actuating lever 31 counterclockwise to bri-ng shoulder 36 into the path of lateral portion 35 of clutch lever 29. Lever 3l' .terminates in an offset `portion 4U (Fig. 2) which portion, upon the energization of phasing magnet 43, :is brought against the periphery of cam disc 52, the .purpose of which, as will presently appear, is -t-o disengage Vend 35 of lever 29 from shoulder 36.

As previously described, gear 2G is normally rotating constantly, Vand as lever 31 is actuated te its counterclockwise position, shoulder 35 thereon is brought into the path of the oncoming portion 35. Thus, when portion 35 strikes against shoulder 36, lfurther rotation of gear 23 will cause clutch lever 29 to rotate slightly in a `counterclockwise direction about its ball and socket pivot connection A5I) against the tension of spiral spring 33. The shouldered or stepped extremity 81 of lever 29 will become disengaged from the square projections 28, thereby permittingy gear 26 tocontinue its rotation idly on shaft 21. The arrestment :of lever .'29 by shoulder 36 will, through arm 32, cause shaft 21 to cease its rotation, hence causing the stoppage of type wheel 34 with a predetermined character position thereon in printing position. When type wheel 34 is thus stopped, the blank position (for example) on its periphery will be presented to the printing point opposite hammer portion 14. As previously mentioned, when the current in magnet 43 is restoredto normal, the armature 39 will still remain in attracted position.

As previously alluded to, the transmitter is arranged to transmit after a time interval 98 (Fig. 6) corresponding to -slightly more than a revolution of the type wheel 34, a recording signal I3 corresponding to the blank position on the type wheel, where it is arrested, or rather substantially in this position since certain timing considerations will likely make it necessary to have the stopping position slightly different from the actual printing position. As soon as the special recording signal I3 is received, magnets 43 and 64 will become de-energized. The apparatus is so designed that the pressure of projection 35 on shoulder 36 of lever 31 is sufficient to hold the armature 39 in attracted Aposition even when magnet 43 is completely de-energized. However, as soon as the recording signal I3 is received, amature 6I is released, whereupon a printing cycle takes place, as previously described, and during the cycle, projection 40 is engaged by one of the cam lobes on printing cam 52, and lever 31 is cammed away and caused to rotate slightly in a clockwise direction to eifect the release of lever 29 therefrom, and then one of the teeth 81 engages a pin 28 so that the type wheel is in the correct phase position and ready to receive regular recording signals I3. Either of the teeth 81 may engage a pin 28, but only one is correct for any given condition.

Although a particular embodiment of the invention has been described herein, it will be understood that the apparatus is capable of many modiiications, and it is contemplated that all forms which come within the range and scope of equivalency are intended to be embraced within the purview of the appended claims.

What is claimed is:

1. In a recorder, a constantly rotating type wheel, signal controlled means to determine the character to be recorded according to the position of the type Wheel when the signal is received, and all-mechanical means local to the recorder to time the operation of the recorder within certain limits of variation in the time of arrival of the signal to insure accurate recording of the character.

2. In a recorder, a shaft, a constantly rotating Y type wheel, a signal controlled means to determine the character to be recorded accordingto the position of the type wheel when the signal is received, a phasing means comprising an engaging means associated with the type Wheel and shaft, normally effective to operatively engage said type wheel and shaft, and a further signal controlled means to disengage said phasing means to enable the arrestment of the type wheel in a predetermined position for phasing.

3. `In a recorder, a constantly rotating type wheel, signal controlled means to determine the character to be recorded according to the positionof the type wheel when the sign-al is received, differential means, and means controlled by said diierential means to time the operation of the recorder within certain limits of variation in the time of arrival of the signal to insure accurate recording of the character.

' 4. In a recorder, aconstantly rotating type wheel, signal controlled means to Ydetermine the character to berecorded according to the position of the type wheel'when a signal is received,

differential gearing, and timingmeans associatedV Y with said gearing to time-the operation Vofithe recorder within certain limits of variation in the time of arrival of the signal to insure accurate recording ofthe character. l

5. In aV recorder, aconstantly rotating type wheel, signal controlled, means to determine thecharacter toL be recorded according to the position-of the type wheel when the signal is received, printing mechanism, planetary gears, and amultitoothed disc for carrying said gears to control the operation of said printing mechanism within certain limits of` variation in the time of arrival ofthe signal to insure accurate recording of the ch-aracter.

6.,In`a recorder,- a constantly rotating type wheel, signal responsive means, a printing control disc, planetary gears carried on said disc, said gears normally ineffective, but effective when said disc is arrested under the control vof said signal responsive means and cam means acting in response to said arrestment to control the printing mechanism to eifect the recordation of a character corresponding to the received signal.

7. In a telegraphrecorder, a type wheel clutch means for driving said type wheel comprising a driving vmeans and a driven means, said driven means comprising an -arm xedly related to said type wheel and pivotally carrying thereon a lever, one end of which is adapted to cooperate with a circular series of lugs on said driving means, an electromagnet, and a lever controlled by saidelectromagnet in response to a signaling condition to cooperate with the other end of saidV lever to disengage said lever from said lugs to stop said typewheel in a predetermined phasing position irrespective of the rotation of said driving means. Y

8. In a telegraph recorder, a normally constantly rotating type wheel, signal controlled means to determine the rcharacter to be recorded according to the position of the type wheel when the signal is received, printing mechanism,V

planetary gears, a multitoothed disc for carrying said gearsto control the operation of said printing mechanism within certain limits of variation in the-time of arrival of the signal to insure accurate recording of the character, clutch means for driving said type wheelcomprising a driving means and a driven means, said driven 'Y r means comprising an arm xedly related to said type wheel and pivotally carrying thereon a lever, one end of which is adapted to cooperate with a circular series of lugs on said driving means, a' signal responsive means in the same circuit with' said signalcontrolled means, a lever controlled by said signal responsive means in `response to 1a' signaling condition to cooperate recorded, means controlled by the de-energiza- ,K

tion of said magnet to record the selected character, and mechanical means effective after the recording operation has Ibeen initiated to return the armature of said magnet to contact with the pole pieces of said magnet.

10. In a telegraph receiver, a type Wheel, means to rotate the type Wheel continuously, a normally energized magnet adapted to be deenergized at varying times according to the character to be recorded, means controlled by the de-energization of said magnet to record the selected character, and cam actuated means effective after the recording operation has been initiated to return the armature of said magnet into Contact with the pole pieces of said magnet.

11. In a recording machine, a set of gears including three elements, means to rotate one element continuously, means effective under certain operating conditions to arrest either of the other elements and cause the remaining element to rotate, a cam carried by one of the arrestable elements, and recording mechanism operated by the cam.

12. In a recording machine, a set of gears including three elements, means to rotate one element continuously, means effective under certain operating conditions to arrest either of the other elements and cause the remaining element to rotate, a cam carried by one of the arrestable elements, recording mechanism operated by said cam, and a signal receiving magnet adapted to control said arresting means.

13. In a recording machine, a set of gears comprising three elements, means to rotate one element continuously, means to arrest either of the other elements and cause the remaining element to rotate, a cam carried by one of the arrestable elements, recording mechanism operated by said cam, a signal receiving magnet adapted to control said arresting means, and means carried by the one of said elements which carries the printing cam to move the record receiving materials to produce character spaces.

14. In a recording machine, a set of gears comprising three elements, means to rotate one element continuously, means to arrest either of the other elements and cause the remaining element to rotate, a'cam .carried by one of the arrestable elements, recording mechanism operated byv said. cam, a signal receiving magnet adapted to control said arresting mean-s, and means carried by the .one of' said elements which carries Ythe printing cam to move the armature of the signal receiving magnet inr one direction.

15. In atelegraphic recorder, a constantly rotating wheel carrying a plurality of recording elements, a signal controlled means to make varying records according to the angular position of the wheel when a signal is received, a'further signal controlled means to disengage the wheel from its driving member, and means cooperating with the first mentioned signal controlled means to `re-engage the wheel and driving member so that each recording member is in a predetermined position when the corresponding signal is received.,

16. In a telegraphic recorder, a constantly rotating wheel carrying a plurality of different recording elements, means for driving said Wheel, signal controlled means to disengage said Wheel from'said driving means, and cam means associated with said driving means to re-engage said wheel in a selected phase position.

17. In a telegraphic recorder, a signal receiving magnet, an armature for the magnet, a printing cam started into operation when the armature moves to its released position, means associated with the printing cam to return the armature of the magnet to the pole pieces of the magnet, and means to insure the completion of theV rotation of the printing cam after the armature has returned to the pole piece of the magnet.

18. In a telegraph receiver, an escapement device operated once for each single impulse character signal, a recording mechanism operated in response :to each operation of the escapement device, and means to maintain the operation of the recording mechanism after the signal has ceased.

19. In a recording device, a shaft, means for rotating said shaft through a xed angle for each recording operation, recording mechanism operated by members mounted on said shaft, and a record material feeding wheel rigidly mounted on said shaft.

20. In a telegraph recorder, a constantly rotating shaft, a type wheel fast to the shaft to rotate therewith, signal controlled means to uncouple the type Wheel from the shaft, and power operated means, eifective after the signal has ceased, to control the recoupling of the type Wheel to the shaft.

21. In a signal receiving device, a magnet, a movable armature associated With said magnet, a spring restraining the armature from movementV toward the magnet when normal signaling current is received and yieldable When a stronger current isl received, and power operated means to positively restore the armature to the position appropriate for normal current. Y

22. In a signal controlled receiver, a type wheel rotating continuously during the reception of recording signals, means for driving said type wheel, means responsive to a certain signal to arrest the type Wheel in a predetermined position, and cam means associated With said driving means and controlled in response to a different signal to start the type Wheel into rotation.

23. In a signal controlled recorder, a constantly rotating shaft, a type wheel normally engaged to the shaft during periods of recording, means to disengage the type wheel from the shaft, and means operated by the recording means in response to the recording signal to re-engage the type Wheel to the shaft.

24. In a recorder, a rotatable type wheel, a

synchronous motor, and gearing between the type` wheel and motor such that the type Wheel moves from one character to the next in an interval equivalent to one-half wave of the alternating current supplied to the motor.

25. In a recorder, a constantly rotating type wheel, signal controlled means to determine the character to be recorded according to the position of the type Wheel when a signal is received, sun and planetary gearing associated with said means, and timed means co-operable with said gearing to time the operation of the recorder within certain limits of variation in the time of arrival of the signal to insure accurate recording of the character.

26. In a printing telegraph apparatusy a type Wheel, a synchronous motor operated by alternating current, and means to couple the type wheel to the motor in a plurality of positions, each position having a relation to a selected phase condition of the alternating current such that the type wheel moves 'from one character to the next in an interval equivalent to one-half Wave cf the alternating current supplied to the motor.

2'7. In a printing telegraph apparatus, a type Wheel, means to start the type Wheel into rotation from a predetermined position at the beginning of a cycle, and means to make a lplurality of impressions on record material during a single rotation of the type wheel.

28. In a recorder, a recording element carrier, means to start the carrier into rotation from a predetermined position at the beginning of a cycle, and means to make a plurality of impressions on record material during a single rotation of the carrier.

29. In a printing telegraph apparatus, a conmeans responsive to a single initial impulse to control the engagement of the type Wheel to the shaft, said means also responsive to a subsequent impulse to control the operation of the print hammer.

31. In a printing telegraph apparatus, a type controlled magnet having a reciprocable armature, and means for mechanically returning said armature to its held position operative con-r certedly with said mechanical means and during a cyclic interval when said print hammer is loaded for a succeeding print operation.

33. In a telegraph printing apparatus, a rotatable shaft, a print hammenmeans carried by said shaft to load and release said hammer for print operation, a signal controlled magnet in.- cluding an armature, and means to periodically restore and release said armature for operation in unison With said print hammer loading and releasing means.

LOUIS M. POTTS. 

